cloudflared-mirror/edgediscovery/allregions/regions.go

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package allregions
import (
"fmt"
"math/rand"
"github.com/rs/zerolog"
)
// Regions stores Cloudflare edge network IPs, partitioned into two regions.
// This is NOT thread-safe. Users of this package should use it with a lock.
type Regions struct {
region1 Region
region2 Region
}
// ------------------------------------
// Constructors
// ------------------------------------
// ResolveEdge resolves the Cloudflare edge, returning all regions discovered.
func ResolveEdge(log *zerolog.Logger, region string, overrideIPVersion ConfigIPVersion) (*Regions, error) {
edgeAddrs, err := edgeDiscovery(log, getRegionalServiceName(region))
if err != nil {
return nil, err
}
if len(edgeAddrs) < 2 {
return nil, fmt.Errorf("expected at least 2 Cloudflare Regions regions, but SRV only returned %v", len(edgeAddrs))
}
return &Regions{
region1: NewRegion(edgeAddrs[0], overrideIPVersion),
region2: NewRegion(edgeAddrs[1], overrideIPVersion),
}, nil
}
// StaticEdge creates a list of edge addresses from the list of hostnames.
// Mainly used for testing connectivity.
func StaticEdge(hostnames []string, log *zerolog.Logger) (*Regions, error) {
resolved := ResolveAddrs(hostnames, log)
if len(resolved) == 0 {
return nil, fmt.Errorf("failed to resolve any edge address")
}
return NewNoResolve(resolved), nil
}
// NewNoResolve doesn't resolve the edge. Instead it just uses the given addresses.
// You probably only need this for testing.
func NewNoResolve(addrs []*EdgeAddr) *Regions {
region1 := make([]*EdgeAddr, 0)
region2 := make([]*EdgeAddr, 0)
for i, v := range addrs {
if i%2 == 0 {
region1 = append(region1, v)
} else {
region2 = append(region2, v)
}
}
return &Regions{
region1: NewRegion(region1, Auto),
region2: NewRegion(region2, Auto),
}
}
// ------------------------------------
// Methods
// ------------------------------------
// GetAnyAddress returns an arbitrary address from the larger region.
func (rs *Regions) GetAnyAddress() *EdgeAddr {
if addr := rs.region1.GetAnyAddress(); addr != nil {
return addr
}
return rs.region2.GetAnyAddress()
}
// AddrUsedBy finds the address used by the given connection.
// Returns nil if the connection isn't using an address.
func (rs *Regions) AddrUsedBy(connID int) *EdgeAddr {
if addr := rs.region1.AddrUsedBy(connID); addr != nil {
return addr
}
return rs.region2.AddrUsedBy(connID)
}
// GetUnusedAddr gets an unused addr from the edge, excluding the given addr. Prefer to use addresses
// evenly across both regions.
func (rs *Regions) GetUnusedAddr(excluding *EdgeAddr, connID int) *EdgeAddr {
// If both regions have the same number of available addrs, lets randomise which one
// we pick. The rest of this algorithm will continue to make sure we always use addresses
// evenly across both regions.
if rs.region1.AvailableAddrs() == rs.region2.AvailableAddrs() {
regions := []Region{rs.region1, rs.region2}
firstChoice := rand.Intn(2)
return getAddrs(excluding, connID, &regions[firstChoice], &regions[1-firstChoice])
}
if rs.region1.AvailableAddrs() > rs.region2.AvailableAddrs() {
return getAddrs(excluding, connID, &rs.region1, &rs.region2)
}
return getAddrs(excluding, connID, &rs.region2, &rs.region1)
}
// getAddrs tries to grab address form `first` region, then `second` region
// this is an unrolled loop over 2 element array
func getAddrs(excluding *EdgeAddr, connID int, first *Region, second *Region) *EdgeAddr {
addr := first.AssignAnyAddress(connID, excluding)
if addr != nil {
return addr
}
addr = second.AssignAnyAddress(connID, excluding)
if addr != nil {
return addr
}
return nil
}
// AvailableAddrs returns how many edge addresses aren't used.
func (rs *Regions) AvailableAddrs() int {
return rs.region1.AvailableAddrs() + rs.region2.AvailableAddrs()
}
// GiveBack the address so that other connections can use it.
// Returns true if the address is in this edge.
func (rs *Regions) GiveBack(addr *EdgeAddr, hasConnectivityError bool) bool {
if found := rs.region1.GiveBack(addr, hasConnectivityError); found {
return found
}
return rs.region2.GiveBack(addr, hasConnectivityError)
}
// Return regionalized service name if `region` isn't empty, otherwise return the global service name for origintunneld
func getRegionalServiceName(region string) string {
if region != "" {
return region + "-" + srvService // Example: `us-v2-origintunneld`
}
return srvService // Global service is just `v2-origintunneld`
}